Updated error handling and value assignment tests

[andreimerlescu]

No description provided.

[Copilot]

Pull Request Overview

Updates error handling with typed error structs, enhances flag value assignment, and expands tests for value parsing and assignment.

• Store persistent pointers for boolean flags and update flag registration
• Replace generic fmt.Errorf errors with ErrLoadFailure/ErrValidationFailure
• Add deep-copy logic in Value.Assign and comprehensive tests for Value.Set

Reviewed Changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
mutations_new.go	Use a persistent pointer for bool flags and update BoolVar call
loading.go	Swap fmt.Errorf for structured load/validation error types
fruit.go	Introduce IsBoolFlag, use ErrInvalidValue, add deep-copy in Assign
errors.go	Define ErrLoadFailure, ErrValidationFailure, ErrValue, and Unwrap methods
conversions.go	Change toInt to reject float strings and check int32 overflow
conversions_test.go	Adjust tests to expect errors on float-to-int parsing
assure.go	Migrate validation errors to use ErrValue with standardized messages
fruit_test.go	New tests covering all Value.Set mutagenesis cases
figtree_test.go	Remove obsolete invalid-bool test cases
VERSION	Bump version from v2.0.13 to v2.0.14

Comments suppressed due to low confidence (1)

fruit.go:182

• [nitpick] You’ve added deep-copy logic for ListFlag and MapFlag in Assign, but there are no tests verifying that mutations of the original flag do not affect the stored Value. Consider adding tests to cover these deep-copy paths.

	case *MapFlag: